At present, 4×103˜9×103 hm2 land is affected by salinization in the world, and 2.6×10711 m2 in China, wherein, around 6.6×103 hm2 land is cultivated land. Land salinization has become an important factor affecting crop growth. Along with the industrial development, quality of irrigation water is degrading, and soil salinization is increasingly exacerbated. Thus, salinization treatment, comprehensive development of saline land, improvement of salt tolerance of plants, and utilization of saline water resource have great impact on plant growth.
Breeding of salt tolerant crops is an effective approach of saline land development and utilization. Main methods of salt tolerant crop breeding in prior art include: domestication of wild salt tolerant plants, traditional breeding, distant hybridization of crops and wild sibling species, mutation selection, genetic engineering breeding, and etc. However, due to insufficient understanding of the biochemical foundations of salt tolerance of plants, salt tolerant crop with practical significance has not been obtained so far.
As molecular biology develops rapidly, the physiological and biochemical mechanisms of plant salt tolerance become explicit, which makes clone of genes relating to plant salt tolerance possible. For example, the patent with the publication number of CN 103204915 B discloses salt tolerance related protein IbEST of sweet potato, its coding gene and its use thereof, wherein said IbEST protein is sourced from sweet potato and the salt tolerance of said protein in other breeds is unknown. For one more example, the patent with the publication number of CN 102796713 B publishes salt tolerance related protein and gene of plants and their application as selection marker, and specifically discloses a plant salt tolerance related protein named GmVP, wherein salt tolerance is shown when said salt tolerance related protein is transcribed into endogen or dicotyledon. However, plant sourced salt tolerant protein or gene has species restriction, and thus their application is limited. However, in prior art, no artificial salt tolerant protein has been reported, and there is no report on artificial salt tolerant protein in transgenic microorganism.